A metal-organic framework with ultrahigh glass-forming ability
نویسندگان
چکیده
Glass-forming ability (GFA) is the ability of a liquid to avoid crystallization during cooling. Metal-organic frameworks (MOFs) are a new class of glass formers (1-3), with hitherto unknown dynamic and thermodynamic properties. We report the discovery of a new series of tetrahedral glass systems, zeolitic imidazolate framework-62 (ZIF-62) [Zn(Im2-x bIm x )], which have ultrahigh GFA, superior to any other known glass formers. This ultrahigh GFA is evidenced by a high viscosity η (105 Pa·s) at the melting temperature Tm, a large crystal-glass network density deficit (Δρ/ρg)network, no crystallization in supercooled region on laboratory time scales, a low fragility (m = 23), an extremely high Poisson's ratio (ν = 0.45), and the highest Tg/Tm ratio (0.84) ever reported. Tm and Tg both increase with benzimidazolate (bIm) content but retain the same ultrahigh Tg/Tm ratio, owing to high steric hindrance and frustrated network dynamics and also to the unusually low enthalpy and entropy typical of the soft and flexible nature of MOFs. On the basis of these versatile properties, we explain the exceptional GFA of the ZIF-62 system.
منابع مشابه
Metal-organic framework materials as nano photocatalyst
Photocatalytic degradation of toxic organic compound in water, soil and air by semiconductor catalysts such as TiO2 and ZnO have received much attention over the last two decades. However, the low quantum yield, easy agglomeration and difficult post-separation of these inorganic catalysts limit their application for large-scale applications. Metal-organic frameworks (MOFs) are the latest class ...
متن کاملMetal-organic framework materials as nano photocatalyst
Photocatalytic degradation of toxic organic compound in water, soil and air by semiconductor catalysts such as TiO2 and ZnO have received much attention over the last two decades. However, the low quantum yield, easy agglomeration and difficult post-separation of these inorganic catalysts limit their application for large-scale applications. Metal-organic frameworks (MOFs) are the latest class ...
متن کاملMechanical Synthesis of Zn-HKUST-1 Metal-Organic Framework and Investigation its Fluorescence Sensing Ability Toward to Detect Explosive-like Nitro aromatic Analytes Such as TNT
Metal-Organic Framework (MOFs) are new crystalline materials which because of having propertiessuch as high porosity, optical and electrical properties, etc., have been considered in areas such as gasstorage, catalysis, pollutants removal and so on. Therefore, in order to develop these compounds andtheir use in this study, in this work, Zn-HKUST-1 metal-organic framework was synthesized by fast...
متن کاملFragility of iron-based glasses
Related Articles The electronic structure origin for ultrahigh glass-forming ability of the FeCoCrMoCBY alloy system J. Appl. Phys. 110, 033720 (2011) Enhancement of glass-forming ability and corrosion resistance of Zr-based Zr-Ni-Al bulk metallic glasses with minor addition of Nb J. Appl. Phys. 110, 023513 (2011) Structural origin underlying poor glass forming ability of Al metallic glass J. A...
متن کاملApplication of a nanoporous metal organic framework based on iron carboxylate as drug delivery system
In the present study, a nanoporous metal organic framework (MOF) based on iron metal and amino terephthalate ligand MIL-101-NH2-Fe has been used as a carrier for loading and in vitro release of 5-flurouracil (5-FU) anticancer drug. The 5-FU drug loaded MOF was 13 wt % by using thermogravimetric analysis (TGA). The 5-FU release was monitored under physiological condition at 37°C, pH 7.4 in simul...
متن کامل